Index
Coefficient
of thermal expansion
Ver: 0
DESCRIPTION
Allows the user to
modify the current value of the thermal expansion coefficient used in non-isothermal
flow problems. Here, the Boussinesq approximation is used and the density
depends linearly upon the temperature. Thus,
ro = r0 * ( 1 - beta
* (T - Tbeta) )
where beta is the coefficient
of thermal expansion; T and Tbeta are the temperature and the reference
temperature, respectively; ro and r0 are the densities at T and Tbeta,
respectively.
By default, beta =
Tbeta = 0.
OPTIONS
|
-1
|
Upper level menu |
|
The current values
are accepted |
|
1
|
Modification of beta |
|
The value of beta
is modified |
|
2
|
Modification of Tbeta |
|
The value of Tbeta
is modified |
NOTES
The coefficient of
thermal expansion is only taken into account if non-vanishing values are
given for the fluid density and the gravity. In some situations, thermal
expansion introduces a coupling between the momentum and energy equations
which makes the problem strongly non-linear. In this case, an evolution
scheme (on beta) might be recommended.
The units for the parameters
beta and tbeta are :
|
Parameter
|
Mass
|
Length
|
Time
|
Temperature
|
|
beta |
-
|
-
|
-
|
-1
|
|
Tbeta |
-
|
-
|
-
|
1
|
SEE ALSO
continuum equations (UM)
Boussinesq approximation
(UM)
evolution (UM)
s-dependence
create
a new task
system
of units
material
data
gravity
density